For the science of static charges see Electrostatics

Static electricity refers to the accumulation of excess electric charge in a region with poor electrical conductivity (an insulator), such that the charge accumulation persists. For the science of static charges see Electrostatics Static electricity refers to the accumulation of excess Electric charge in a Electrostatics is the branch of Science that deals with the Phenomena arising from what seems to be stationary Electric charges Since Classical Electric charge is a fundamental conserved property of some Subatomic particles which determines their Electromagnetic interaction. Electrical conductivity or specific conductivity is a measure of a material's ability to conduct an Electric current. An insulator, also called a Dielectric, is a material that resists the flow of Electric current. The effects of static electricity are familiar to most people because we can see, feel and even hear the spark as the excess charge is neutralized when brought close to a large electrical conductor (for example a path to ground), or a region with an excess charge of the opposite polarity (positive or negative). In Science and engineering, a conductor is a material which contains movable Electric charges. In Electrical engineering, the term ground or earth has several meanings depending on the specific application areas

Contents 1 History 2 Causes of static electricity 2.1 Contact induced charge separation 2.2 Pressure induced charge separation 2.3 Heat induced charge separation 2.4 Charge induced charge separation 3 Static discharge 3.1 Lightning 4 Simple experiments 4.1 Charged adhesive tape 5 Applications 6 Risks 6.1 Electronic components 6.2 The chemical industry 6.3 Space exploration 6.4 Fueling Operations 6.5 Mobile Phones and Gasoline Pumps 6.6 Ozone cracking 7 See also 8 References

History

Main article: History of electricity

The natural phenomenon of static electricity was known at least as early as the 6th century BC, as attested by Thales of Miletus. Thales of Miletus According to Bertrand Russell, "Philosophy begins with Thales Scientific research into the subject began when machines were built to create it artificially, such as the friction generator developed by Otto von Guericke in the 17th century. Otto von Guericke (originally spelled Gericke ˈgeːʁɪkə ( November 20, 1602 &ndash May 11, 1686 ( Julian calendar) The connection between static electricity and storm clouds was famously demonstrated by Benjamin Franklin in 1750 ^{[1] [2]}. Benjamin Franklin ( April 17 1790 was one of the Founding Fathers of the United States of America. In 1832, Michael Faraday published the results of his experiment on the identity of electricities, which proved that the electricity induced using a magnet, voltaic electricity produced by a battery, and static electricity were all the same. Michael Faraday, FRS ( September 22 1791 – August 25 1867) was an English A magnet (from Greek grc μαγνήτης λίθος " Magnesian stone" is a material or object that produces a Magnetic field. In electronics a battery is a combination of two or more Electrochemical cells which store chemical Energy which can be converted into electrical energy Since Faraday's result, the history of static electricity merged with the study of electricity in general.

Causes of static electricity

The materials we observe and interact with from day-to-day are formed from atoms and molecules that are electrically neutral, having an equal number of positive charges (protons, in the nucleus) and negative charges (electrons, in shells surrounding the nucleus). History See also Atomic theory, Atomism The concept that matter is composed of discrete units and cannot be divided into arbitrarily tiny In Chemistry, a molecule is defined as a sufficiently stable electrically neutral group of at least two Atoms in a definite arrangement held together by The proton ( Greek πρῶτον / proton "first" is a Subatomic particle with an Electric charge of one positive The nucleus of an Atom is the very dense region consisting of Nucleons ( Protons and Neutrons, at the center of an atom The electron is a fundamental Subatomic particle that was identified and assigned the negative charge in 1897 by J An electron shell may be crudely thought of as an Orbit followed by Electrons around an Atom nucleus. The phenomenon of static electricity requires a sustained separation of positive and negative charges.

Contact induced charge separation

Main article: Triboelectric effect

Electrons can be exchanged between materials on contact; materials with weakly bound electrons tend to lose them, while materials with sparsely filled outer shells tend to gain them. Triboelectric Series Materials are often listed in order of the polarity of charge separation when they are touched with another object This is known as the triboelectric effect and results in one material becoming positively charged and the other negatively charged. Triboelectric Series Materials are often listed in order of the polarity of charge separation when they are touched with another object The polarity and strength of the charge on a material once they are separated depends on their relative positions in the triboelectric series. Triboelectric Series Materials are often listed in order of the polarity of charge separation when they are touched with another object The tribo electric effect is the main cause of static electricity as observed in everyday life, and in common high-school science demonstrations involving rubbing different materials together (e. g. fur and an acrylic rod).

Pressure induced charge separation

Main article: Piezoelectric effect

Certain types of crystals and ceramics generate a separation of charge in response to applied mechanical stress. Piezoelectricity is the ability of some materials (notably Crystals and certain Ceramics including bone to generate an Electric potential in response to In Materials science, a crystal is a Solid in which the constituent Atoms Molecules or Ions are packed in a regularly ordered repeating The word ceramic is derived from the Greek word κεραμικός ( keramikos)

Heat induced charge separation

Main article: Pyroelectric effect

Certain materials generate a separation of charge in response to heating. Pyroelectricity is the ability of certain materials to generate an Electrical potential when they are heated or cooled All pyroelectric materials are also piezoelectric, the two properties being closely related.

Charge induced charge separation

Main article: Electrostatic induction

A charged object brought into the vicinity of an electrically neutral object will cause a separation of charge within the conductor as charges of the same polarity are repelled and charges of the opposite polarity are attracted. Electrostatic induction is a redistribution of Electrical charge in an object caused by the influence of nearby charges As the force due to the interaction of electric charges falls off rapidly with increasing distance, the effect of the closer (opposite polarity) charges is greater and the two objects feel a force of attraction. The effect is most pronounced when the neutral object is an electrical conductor as the charges are more free to move around. In Science and engineering, a conductor is a material which contains movable Electric charges.

Careful grounding of part of an object with a charge induced charge separation can permanently add or remove electrons, leaving the object with a global, permanent charge. This process is integral to the workings of the Van de Graaf Generator, a device commonly used to demonstrate the effects of static electricity. A Van de Graaff generator is an electrostatic machine which uses a moving belt to accumulate very high electrostatically stable Voltages on a hollow metal globe

Static discharge

Main article: Electrostatic discharge

The spark associated with static electricity is caused by electrostatic discharge, or simply static discharge, as excess charge is neutralized by a flow of charges from or to the surroundings. The Wimshurst machine is an electrostatic device for generating high Voltages developed between 1880 and 1883 by British Inventor James Wimshurst Electrostatic discharge ( ESD) is the sudden and momentary Electric current that flows between two objects at different Electrical potentials The term is In general, significant charge accumulations can only persist in regions of low electrical conductivity (very few charges free to move in the surroundings), hence the flow of neutralizing charges often results from neutral atoms and molecules in the air being torn apart to form separate positive and negative charges which then travel in opposite directions as an electric current, neutralizing the original accumulation of charge. Air typically breaks down in this way at around 30,000 volts-per-centimetre depending on humidity. The volt (symbol V) is the SI derived unit of electric Potential difference or Electromotive force. ^[3] The discharge superheats the surrounding air causing the bright flash, and produces a shockwave causing the clicking sound.

The feeling of a static electric shock is caused by the stimulation of nerves as the neutralizing current flows through the human body. Due to the ubiquitous presence of water in places inhabited by people, the accumulated charge is generally not enough to cause a dangerously high current.

Lightning

Main article: Lightning

Lightning is a dramatic natural example of static discharge. Lightning is an atmospheric discharge of Electricity, which typically occurs during Thunderstorms and sometimes during volcanic eruptions or While the details are unclear and remain the subject of debate, the initial charge separation is thought to be associated with contact between ice particles within storm clouds. Whatever the cause may be, the resulting lightning bolt is simply a scaled up version of the sparks seen in more domestic occurrences of static discharge. The flash occurs because the air in the discharge channel is heated to such a high temperature that it emits light by incandescence. Incandescence is the emission of Light (visible Electromagnetic radiation) from a hot body due to its temperature The clap of thunder is the result of the shockwave created as the superheated air rapidly expands. Thunder is the sound made by Lightning. Depending on the nature of the lightning and distance of the listener it can range from a sharp

Simple experiments

Note: a humid atmosphere provides a conducting path for the rapid neutralization of static charge; hence the following examples work best in dry, winter conditions.

Static electricity is notable as a physical phenomenon that can be demonstrated using simple experiments that can convey genuine understanding of the physics involved. ^[4]

Charged adhesive tape

Repulsion between lengths of tape with like charges

Attraction between lengths of tape with opposite charges

A simple and illuminating example of the effects of static electricity can be observed using adhesive tape (such as Scotch tape, on the negative side of the triboelectric series, hence tends to gain electrons and acquire negative charge) charged by peeling. Pressure sensitive tape, PSA tape, Adhesive tape, Self stick tape, Sticky tape consists of a Pressure sensitive adhesive coated Scotch Tape is used to describe certain Pressure sensitive tapes manufactured by 3M as part of the company's Scotch brand ^[5]

If a length of tape adhered to a smooth surface is rapidly peeled off, the tape will acquire an excess negative charge (generally polypropylene with an acrylic adhesive^[6]). Polypropylene or polypropene ( PP) is a Thermoplastic Polymer, made by the Chemical industry and used in a wide variety of applications Do this with two lengths of tape and they will repel each other, demonstrating the fact that like charges repel. Each individual length of tape will experience a small attraction to almost any object as the presence of the excess negative charge induces a charge separation in nearby objects. For the science of static charges see Electrostatics Static electricity refers to the accumulation of excess Electric charge in a Negative charges are pushed further away, while positive charges are attracted, and the strength of the attractive and repulsive forces falls off quite rapidly with distance. In Physics, a force is whatever can cause an object with Mass to Accelerate. In Physics, an inverse-square law is any Physical law stating that some physical Quantity or strength is inversely proportional This effect is most pronounced in materials such as metals, that conduct electricity, as the negative charges are free to move within the material. The M acro E xpansion T emplate A ttribute L anguage complements TAL, providing macros which allow the reuse of code across In Science and engineering, a conductor is a material which contains movable Electric charges.

Finally, try attaching two lengths of tape together, exhaling on them along the entire length to neutralize the charge, then rapidly pulling them apart. There will be some imbalance in the distribution of negative charge between the two pieces such that one is more positive and the other more negative; you should now find that the two lengths of tape attract each other, demonstrating the fact that opposite charges attract. Attaching the adhesive side of one length of tape to the non-adhesive side of the other reduces the chance of tearing and increase the charge imbalance, and hence the strength of the attractive force.

Applications

Static electricity is commonly used in xerography, air filters (particularly electrostatic precipitators), and some automotive paints. Xerography (or electrophotography) is a Photocopying technique developed by Chester Carlson in 1938 and Patented on October 6 An air filter is a device which removes solid Particulates such as Dust, Pollen, Mold, and bacteria from Air. An electrostatic precipitator (ESP or electrostatic air cleaner is a Particulate collection device that removes particles from a flowing gas (such as air using

In the 1963 British science-fiction television serial "Doctor Who", an alien creature encased in metal called a Dalek was powered by static electricity. Doctor Who is a British science fiction television programme produced by the BBC. A Dalek (, ˈdɑːlεk is a member of a Fictional extraterrestrial race of Mutants from the British science fiction television

Risks

Despite the apparently innocuous nature of static electricity as we generally experience it, there can be significant risks associated with it in circumstances where large charges may accumulate in the presence of sensitive materials or devices.

Electronic components

Many semiconductor devices used in electronics are extremely sensitive to the presence of static electricity and can be damaged by a static discharge. Semiconductor devices are Electronic components that exploit the electronic properties of Semiconductor materials principally Silicon, Germanium

The chemical industry

Discharge of static electricity can create severe hazards in those industries dealing with flammable substances, where a small electrical spark may ignite explosive mixtures with devastating consequences. ^[7]

Factories dealing with large quantities of finely powdered substances in the presence of combustible or explosive materials. Major incidents occurred at a grain silo in southwest France, a paint plant in Thailand, and a factory making fiberglass mouldings in Canada. A silo is a structure for storing bulk materials. Silos are used in Agriculture to store grain (see Grain elevators or fermented feed Fiberglass (also called fibreglass and glass fibre see Spelling differences) is material made from extremely fine Fibers of Glass. ^[8]

Space exploration

Due to the extremely low humidity in extraterrestrial environments, very large static charges can accumulate, causing a major hazard for the complex electronics used in space exploration vehicles. Static electricity is thought to be a particular hazard for astronauts on planned missions to the Moon and Mars. The Vision for Space Exploration is the United States space policy announced on January 14, 2004 by U Walking over the extremely dry terrain could cause them to accumulate a significant amount of charge; reaching out to open the airlock on their return could cause a large static discharge, potentially damaging sensitive electronics. ^[9]

Fueling Operations

Static electricity can build up and discharge into fuel. Fuel is any material that is burned or altered in order to obtain energy If the voltage of the discharge is high enough, it can actually ignite the fuel or vapor. Electrical tension (or voltage after its SI unit, the Volt) is the difference of electrical potential between two points of an electrical This is a present danger at gas stations. A filling station, fueling station, gas station, service station, petrol station, or gasbar, Retail Outlet It is one of the reasons why one should not leave their car running while fueling. This type of accident has occurred in the past at gas stations. Fires have also been started at airports while refueling aircraft. New technologies now help prevent static electricity from forming and/or discharging.

Mobile Phones and Gasoline Pumps

Although there have been numerous media reports, emails, laws, and posted warnings at gasoline pumps about the risk of fire caused by mobile phones, there has not been a confirmed case of an electrical discharge from a mobile phone ever causing a fire or explosion among gasoline fumes. To date, it is simply an urban legend. ^[10]

Ozone cracking

Many elastomers are sensitive to ozone cracking, which causes deep penetrative cracks to grow into critical components like gaskets and O-rings. An elastomer is a Polymer with the property of Elasticity. The term which is derived from elastic polymer, is often used interchangeably with the term Cracks can be formed in many different Elastomers by Ozone attack and the characteristic form of attack of vulnerable rubbers is known as ozone cracking. A gasket is a mechanical seal that fills the space between two objects generally to prevent leakage between the two objects while under compression. An o-ring, also known as a packing or a toric joint, is a mechanical Gasket in the shape of a Torus; it is a loop of Elastomer with Fuel lines are also susceptible to the problem unless preventative action is taken. A fuel line is a hose used to bring Fuel from one point in a vehicle to another This includes adding anti-ozonants to the rubber mix, or using an ozone-resistant elastomer. Fires from cracked fuel lines have been a problem on vehicles, especially in the engine compartments where ozone can be produced by electrical equipment. Static discharge will also create ozone, which can then attack rubber parts. OZONE is an object oriented Operating system written in the C programming language.

See also

• Electrical charge
• Electrostatics
• Electrostatic generator
• Electrostatic discharge
• Wimshurst machine

References

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